[b:35lca8va]Detailed description:[/b:35lca8va]
In many games (particularly racing simulations) it is desireable to model the frequency-dependant attenuation of air.

[b:35lca8va]Solution 1:[/b:35lca8va]
1. Use the 3D Auto Distance Filtering effect. In Designer 2010, this is a pair of event properties, ‘3D Auto Distance Filtering’ and ‘3D Auto Distance Centre Freq.’ In the programmer’s API, it can be enabled on all 3D sounds with FMOD_INIT_DISTANCE_FILTERING, tuned with the distanceFilterCentreFreq member of the FMOD_ADVANCEDSETTINGS struct and FMOD::Channel::set3DDistanceFilter().
This uses the built-in lowpass and an extra highpass filter to achieve a bandpass effect.

[b:35lca8va]Solution 2:[/b:35lca8va]
1. Use the FMOD Lowpass Simple DSP (FMOD_DSP_LOWPASS_SIMPLE).
The Lowpass Simple DSP is a single pole filter. By contrast, FMOD_DSP_LOWPASS is a fourth-order Linkwitz-Riley crossover, and therefore too steep for this purpose under most circumstances.

[b:35lca8va]Notes:[/b:35lca8va]
A description of all FMOD’s DSPs can be found under ‘Enumerations’ in the Programmer’s API Documentation.